I think, almost everybody, who has an AMD/ATI graphics card, has already heard about the new RadeonHD Linux Driver, but not everyone has already tested it.
For my part I'm testing since yesterday and the whole thing is growing very fast, however I do not yet have a proper output on my Mobility Radeon X1400. But this is not what I wanted to write here, I wanted to write how to help the developers.

IMPORTANT!
First you need to send some beer, some peanuts and maybe also some money to libv (#radeonhd on freenode), then he might start looking on your reports g - sorry libv ;) just kiddin too ;)

1. get the driver
As the driver is in a very early stage of development, changes are made every day and packages from your distribution (well, I only know that Debian has it in it's repositories) is maybe outdated at the time of uploading by the maintainer, so please build it from git, as perfectly described here at phoronix.

2. test the driver
a) You get a picture when starting X with the radeonhd driver? Feel lucky and maybe write an email to radeonhd@opensuse.org, telling the guys how much you love them, and what card works for you.
b) You get a black screen, but X has properly started? The driver has correctly recognized your card, but had problems to set-up correctly, please read on.
c) You get an error in your log, and no X? That might have several reasons, let's look in your log. Does it state something like

If so, your card could not be recognized, as every vendor (ASUS, Gecube, etc) might give the card a slightly different subsystem id, which is not yet known to the driver. Please have a look at reporting card info, so your card can soon be added to the driver.
Or do you probably get something like

(EE) RADEONHD(0): No valid modes found?

This should happen, when the driver could not get enough/correct information, what mode you monitor wants to run with, this does lead to the previously described black screen too (as I get it here at the moment). I do not think this should be reported at the moment, as the problem is known to the developers.

3. reporting card info
When you decide to report something (which is the real help-part here), you should do it correctly.
First you should describe what card do you have (not only Radeon X1950, but ASUS FunkyNameOnTheBox Radeon X1950), and what result do you get (working X, not working X, X not finding something, etc).
Then attach your logfile (usually it's /var/log/Xorg.0.log), but don't forget to compress it before, this really saves traffic.
The last one is probably the most important one: the conntest output (see below).

4. conntest
conntest is a small tool which probes the connectors of the video card.
You can find it in utils/conntest/ in git, and build it just by calling make (dont forget to install pciutils-dev).
The you call it with ./rhd_conntest <pci tag> as root, where <pci tag> is the number lspci shows you in front of the name of your card - usually it is 01:00.0
But you should not run it just once, but for every output your card have.
On a laptop it's usualy once with nothing attached (only internal screen is active), and once with a screen connected to the VGA port.
If your laptop has a DVI and not a VGA connector, please run rhd_conntest once for a analog screen connected through an DVI-VGA adapter, and once for a digital DVI-connected screen.
On a desktop, you would call it once for NO screens connected, and then same as for a laptop: once with a analog screen on each VGA connector and then once with an analog screen with a DVI-VGA adapter and once with a digital screen on each DVI connector.
Have a look at the README in the same dir, it describes everything a bit more.

As soon as you have all the data you want to share, send the mail to radeonhd@opensuse.org and wait for a reply.

About 2 years ago I set up a desktop for my girlfriend (at that time, but this does not matter) with Sarge, which was later upgraded to Etch (this was some time after the freeze but before the release). She is pretty happy with it, but time to time she asks me for a bit of help.

Today she got a RAR-archive from a friend (Windows user). As it was too big for mailing, he protected it with a password and uploaded it to some public space. Nothing unusual, open file in file-roller, click extract, put password into the appropriate field, and you're done.

Not with this file, 'file-roller filename.rar' opens a dialog box saying: "this file is password protected. please enter the password under 'edit->password'". Well, this menu-item is grayed out, so file-roller does not help us.
As I'm some kilometers away, and have only SSH (well, I could go out for a walk, but not only for a damn archive-password...) to the box, let's try rar from non-free, this is "real" rar, it should support it. It does, as it correctly asks for a password, but fails because the password contains German umlauts. And yeah, I did set the right locales, everything UTF-8, both my side and the remote side. And yes I tried ISO-8859 too.
Next try is p7zip-full, as it supports RAR archives. But not this one? With UTF-8 it asks for a password, gets one, tells me which file it will extract and dies with "Unsupported Method". With ISO-8859 it just says incorrect password...
WTF? But what's about fetching the file and extracting it locally on my Sid system? Got the file, and extracted it with rar (on UTF-8 locale) without problems... With the same version of rar as in Etch!? Holy crap, don't ask me how THIS works. And no, p7zip-full from Sid did not like it, same problem as with the Etch version.

So what do we learn?
1. Fucking non-free proprietary archivers are fucking evil - don't use them!
2. Passwords should never contain non-ASCII characters! ("M,!z6-u_0" is a fine password, which you can type on every keyboard, "Hallö" isn't - try this on a keyboard in India, or maybe just France?)

As already posted today, I now has (sorry jesse, it's just so fuckin' lol ;)) XRandR 1.2 support in my radeon driver.

The card in my laptop (IBM [not Lenovo!] ThinkPad X31) is a ATI Technologies Inc Radeon Mobility M6 LY (a Radeon Mobility 7000) with a 1024x768 12" TFT. As 1024x768 is kinda small for everyday work, I have a 19" TFT with a 1280x1024 resolution on my table.
Until today the second screen had to be connected to the laptop before Xorg started, so MergedFB could recognize and configure it. This is very annoying and it could be simplier... With XRandR 1.2 it IS! I just need to start my box as usual, open a terminal and runxrandr --output VGA-0 --right-of LVDS --mode 1280x1024 --rate 60 (the --rate is special for my TFT, as it supports up to 75Hz, but is a bit blurry then, 60 works perfectly)BUT: xrandr: screen cannot be larger than 1600x1200 (desired size 2304x1024)
WTF?! Kay, let's google around... Ah, fine I need to set my virtual screen to something bigger. So let's open /etc/X11/xorg.conf, find the Screen section, there the subsection Display and edit:
SubSection "Display"
Depth 24
Modes "1024x768" "800x600" "640x480"
Virtual 2304 1024
EndSubSection

Restart Xorg, and have fun with your nice XRandR radeon :>

BTW, this is my third blogpost today, "I can has an award plz!? KTHXBYE" (sorry again, jesse)